Vent baffles are utilized in building structures to vent an area beneath the roof between a soffit and a peak of the building to prevent moisture buildup. Moisture in the roof can potentially damage attic insulation and the building structure itself. Proper ventilation aids in the prevention of premature melting of snow accumulated on a roof. Premature snow melting may lead to the formation of ice on the roof, which is a potential safety hazard and may also damage the roof.
Providing attic ventilation for cathedral ceilings presents unique challenges because drywall or alternative wall boards are secured directly to the inner sides of the roof rafters, leaving a relatively small space between the drywall or wallboards and the roof sheathing of the building. Accordingly, this space is relatively small and must accommodate venting structure and insulation. Conventional cathedral ceilings typically are constructed utilizing ventilation sheets mounted in an end-to-end configuration to the roof sheathing, insulation positioned over the ventilation sheets and drywall or other ceiling sheets mounted to a bottom of the rafters over the insulation. Such installation is labor intensive and misalignment of the vent sheets could potentially inhibit or block the desired flow of air in channels created by the vent sheets from the soffit area to the outlet or ridge of the building structure. Air flow may be blocked if insulation creeps between gaps created between misaligned end-to-end vent sheets, thereby defeating the purpose of or severely limiting the effectiveness of the vent sheets.
Cathedral ceilings may include an attic space near the soffit area of the building proximate the top of the wall and the lower edge of the roof. This area may be insulated by conventional blown insulation that rests on the floor of the attic. Such blown insulation is preferably protected from wind that blows into the soffit area of the building. Uncontrolled air currents circulating in the attic space can have a negative effect on the performance of the attic insulation by promoting increased convective heat transfer along the top surface of the insulation. A roof ventilation system for blocking air from disturbing the blown insulation and enhancing ventilation of the attic space in the soffit area is described in U.S. Pat. No. 7,094,145, granted to Palle Rye, et al on Aug. 12, 2006, from a patent application filed on Mar. 29, 2004, which is co-owned with the instant application and is incorporated herein in its entirety by reference. U.S. Pat. No. 7,094,145 describes a vent baffle and method of installation that may be utilized in the soffit area of a building structure; however, this vent baffle may also be utilized in building structures having a cathedral ceiling-type construction.
A roof constructed of a water impervious outer layer and a water impervious inner layer with an insulating layer therebetween is formed with ventilating channels in U.S. Pat. No. 2,855,869, granted to Carl Munters, et al on Oct. 14, 1958. These ventilating channels extend from the eaves to the wall header along the width of the roof to remove moisture from the insulating layer. The ventilation baffle in U.S. Pat. No. 4,096,790, granted on Jun. 27, 1978, to Laurence Curran, is secured to the tops of the rafters by the roof sheathing and includes a vertical flap that is secured to the sill at the top of the wall to prevent insulation from entering the soffit area from the interior of the building.
U.S. Pat. No. 5,596,847, issued on Jan. 28, 1997, to Michael Stephenson, discloses a polystyrene foam vent structure that is formed with longitudinal ribs, one of which includes a score line to permit the vent panel to be cut into a size that conforms to a smaller spacing of the roof rafters. The vent panel is placed on top of adjacent rafters to provide an air space past the insulation layer. A similar vent panel is taught in U.S. Pat. No. 6,347,991, issued to Blake Bogrett, et al, on Feb. 19, 2002, in which the PVC panel is formed with a central rib to be mounted on top of adjacent roof rafters to provide an air space past the insulation layer. This PVC vent panel is also formed with a hinged chute segment that can be folded downwardly to be affixed to the top sill or the wall to provide an insulation dam. Multiple fold lines in the hinged chute segment provide flexibility in the attachment of the insulation dam.
U.S. Patent Publication No. 2005/0072072 of Richard Duncan, et al, published on Apr. 7, 2005, discloses a baffle vent that is mounted between two adjacent rafters by a friction fit. This baffle vent is also formed with a central longitudinal rib and transverse thickened supports to provide lateral support and stability. A transversely extending perforation is located along one of the transverse supports to permit the baffle vent to be separated along the perforation to form a baffle vent having a shortened length.
The nature of the construction and configuration of a cathedral ceiling requires air ventilation along the entire length of the cathedral ceiling area of the building structure or, at times, from the soffit area to the peak of the building structure. There is a need for a cathedral ceiling vent baffle that is inexpensively manufactured, effectively provides ventilation for the cathedral ceiling, provides a space for insulation between the drywall and roof sheathing of the cathedral ceiling, is quickly and easily installed, and is adaptable for a wide range of cathedral ceiling building configurations.